Tobacco filler is conventionally supplied to a group of cigarette making machines from a single feeder unit. The feeder separates the tobacco for the respective machines and a centrifugal exhaust fan draws the separated tobacco in separate air streams from the feeder to the machines. A tobacco discharger on each machine receives the incoming air stream and entrained tobacco for the machine, screens out and retains the tobacco, and permits the screened air to continue on to the exhaust fan. The discharger cannot release the retained tobacco for use by its machine, as required at fairly frequent intervals, without stopping the flow of air through the discharger while each release is completed. This is done by closing a valve on the air outlet from the discharger, thus isolating the discharger from the fan suction which would otherwise close an outlet door from the discharger to its machine. The result is to stop all air flow from the feeder to that discharger. If that happens in the case of more than one discharger at the same time, as occasionally occurs, the velocity and quantity of air drawn through the other dischargers increases, which tends to break the tobacco being drawn to the other dischargers. If all of the air outlet valves in the group happen to be closed simultaneously, for a prolonged period, such as lunchtime, the resultant loss in air flow may cause the fan to overheat.
When air to a discharger stops flowing the tobacco in that air comes to rest where it is along the line. This results in segregation by particle size and concentration of small pieces at one end or side of the discharger when air flow to the discharger resumes and carries the tobacco which had been at rest in the line into the discharger. Another problem is that the tobacco in conventional feeders may bridge and clump in the feeder if it continues to supply tobacco to less than all the outlets it is designed to feed. Segregation of the various sized particles may also occur.